首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1797篇
  免费   94篇
  国内免费   15篇
耳鼻咽喉   67篇
儿科学   94篇
妇产科学   165篇
基础医学   167篇
口腔科学   76篇
临床医学   144篇
内科学   304篇
皮肤病学   24篇
神经病学   103篇
特种医学   99篇
外科学   400篇
综合类   25篇
预防医学   32篇
眼科学   68篇
药学   64篇
肿瘤学   74篇
  2024年   8篇
  2023年   18篇
  2022年   16篇
  2021年   49篇
  2020年   32篇
  2019年   52篇
  2018年   74篇
  2017年   61篇
  2016年   87篇
  2015年   93篇
  2014年   86篇
  2013年   133篇
  2012年   159篇
  2011年   165篇
  2010年   90篇
  2009年   90篇
  2008年   141篇
  2007年   155篇
  2006年   129篇
  2005年   92篇
  2004年   69篇
  2003年   49篇
  2002年   21篇
  2001年   5篇
  2000年   5篇
  1999年   8篇
  1998年   4篇
  1997年   5篇
  1996年   3篇
  1995年   2篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
排序方式: 共有1906条查询结果,搜索用时 15 毫秒
11.
12.
Background: Postoperative vomiting (POV) is a common complication after tonsillectomy. Dexamethasone is known to decrease postsurgical vomiting. In this study, we compared the effects of dexamethasone alone to dexamethasone plus propofol on postoperative vomiting in children undergoing tonsillectomy. Methods: In a randomized double‐blinded study, we evaluated 80 healthy children, aged 4–12 years, who underwent tonsillectomy with or without adenoidectomy. After anesthesia was induced by inhalation of sevoflurane, 0.15 mg·kg?1 dexamethasone and 2 μg·kg?1 fentanyl was administered i.v. to all patients. The patients in the dexamethasone plus propofol group received 1 mg·kg?1 propofol before intubation and continuously after intubation at a rate of 20 μg·kg?1·min?1 until the surgery was completed. Data for postoperative vomiting were grouped into the following time periods: 0–4 and 4–24 h. Data were analyzed using a Student’s t‐test and chi‐squared analysis. Results: The percentage of patients exhibiting a complete response (defined as no retching or vomiting for 24 h) increased from 37.5% in the dexamethasone‐alone group to 75% in the dexamethasone plus propofol group (P = 0.001). Twenty‐two patients (55%) in the dexamethasone‐alone and nine patients (22.5%) in the dexamethasone plus propofol groups experienced vomited during 0–4 h (P = 0.003). Eight patients in the dexamethasone‐alone group and three patients in the dexamethasone plus propofol group received ondansetron as a rescue antiemetic during the postoperative period. Conclusion: For children undergoing tonsillectomy, intraoperative subhypnotic propofol infusion combined with dexamethasone treatment provides a better prophylaxis against postoperative vomiting than does dexamethasone alone.  相似文献   
13.
Objective To evaluate the relationship between the expression of E-cadherin (E-CD) and tumor recurrence and progression in patients with high-grade stage T1 urothelial carcinoma of bladder. Methods Fifty-two patients who had primary high-grade stage T1 urothelial carcinoma were enrolled to the study. The pathologic specimens of patients were evaluated and staged as T1a and T1b according to muscularis mucosae involvement by the tumor. The immunohistochemical demonstration of E-CD was accomplished by using immunoperoxidase method and all the specimens were examined under light microscope for E-CD level. Results The mean age of the patients was 64.0 ± 7.7 (range 36–81) years. The mean follow-up period was 56.4 ± 19.4 (range 14–84) months. Among 52 patients, 27 (52%) of them were stage T1b and 25 (48%) were T1a tumors. The recurrence rates for T1a and T1b groups were 52% (n = 13) and 92.6% (n = 25), respectively (P < 0.05). The expression of E-CD was homogenous in 52% of pT1a and 14.8% of T1b tumors (P < 0.05). In T1a group with recurrence, homogeneous E-CD staining ratio was 30.7% (n = 4/13), but it was 75% (n = 9/12) in T1a patients without recurrence (P < 0.05). In T1b group with recurrence, the homogenous expression of E-CD was 12% (n = 3/25) and the expression of E-CD was heterogenous in 88% (n = 22/25) of them (P < 0.05). In T1a group, progression of the disease was detected in 28% (n = 7/25) of the patients, but disease progression was seen in 55.5% (n = 15/27) of T1b group patients (P < 0.05). In T1a group with progression, heterogeneous E-CD staining ratio was 85.7% (n = 6/7), but it was 80% (n = 12/15) in T1b patients with progression. The effects of tumor number, tumor size and carcinoma in situ presence on recurrence were evaluated within each group. It was determined that parameters such as tumor number and tumor size had no significant effect on recurrence of the groups. The mean survival rates were statistically different between the groups. On multivariate analysis only E-cadherin expression (P = 0.012, odds ratio 6.291, 95% confidence interval for odds ratio 1.303–4.72) and tumor stage (P = 0.003, odds ratio 11.58, 95% confidence interval for odds ratio 2.446–8.542) remained independently significant as predictors of recurrence. Conclusion E-CD expression was decreased in pathologic specimens of bladder tumor patients with muscularis mucosae involvement and this condition correlated well with tumor recurrence.  相似文献   
14.
BACKGROUND: We aimed to investigate the potential protective effect of remote ischemic preconditioning (IPC) on delayed colonic anastomotic healing induced by remote ischemia and reperfusion (I/R) injury. MATERIALS AND METHODS: Forty male Wistar rats were randomly assigned into four groups, each consisting of 10 rats: the control group (C), the remote I/R group [I/R, 40 min of superior mesenteric artery (SMA) occlusion], the preconditioned I/R group (IPC, two cycles of 5 min temporary occlusion of SMA before an ischemic insult of 40 min), and the preconditioned group (PC, two cycles of 5 min temporary occlusion of SMA). Colonic anastomosis was performed immediately after the ischemic insult. Anastomotic healing was assessed on postoperative day 7 by determining anastomotic bursting pressure (ABP), tissue hydroxyproline content, histopathological examination, malondialdehyde (MDA), and nitric oxide levels. RESULTS: Remote I/R injury resulted with significant impairment in anastomotic healing in terms of mean ABP (P = 0.004), hydroxyproline content (P = 0.002), histopathological healing score (P = 0.001), nitric oxide level (P = 0.010), and MDA levels (P = 0.0001) when compared with the control group, but remote IPC did not improve all above mentioned parameters (P = NS for all), except MDA level (P = 0.011) when compared with I/R group. PC alone impaired the ABP (P = 0.0001), but it did not significantly change the other parameters measured (P = NS). CONCLUSIONS: The results of this study showed that remote IPC did not prevent I/R-induced delaying in colonic anastomotic healing.  相似文献   
15.
The aim of the study is to evaluate the efficacy and safety of retrograde intrarenal surgery (RIRS) to treat renal stones in preschool age (<7 years) children. From September 2005 to May 2013, a total of 65 children (31 boys and 34 girls) with 72 renal stones were treated using RIRS. Patients were considered stone-free when the absence of residual fragments was observed on imaging studies. In the presence of residual calculi >4 mm, a second-stage RIRS was performed. The pre-operative, operative and post-operative data of the patients were retrospectively analyzed. A total of 65 patients with a mean age of 4.31 ± 1.99 years (6 months–7 years) were included in the present study. The mean stone size was 14.66 ± 6.12 mm (7–30 mm). The mean operative time was 46.47 ± 18.27 min. In 5 (7.69 %) patients, the initial procedure failed to reach the renal collecting system and ended with the insertion of a pigtail stent. The stone-free rates were 83.07 and 92.3 % after the first and second procedures, respectively. Complications were observed in 18 (27.7 %) patients and classified according to the Clavien system. Post-operative hematuria (Clavien I) occurred in 6 (9.2 %) patients, post-operative urinary tract infection with fever (Clavien II) was observed in 10 (15.4 %) patients, and ureteral wall injury (Clavien III) was noted in 2 (3 %) patients. RIRS is an effective and safe procedure that can be used to manage renal stones in preschool age children.  相似文献   
16.
17.
Introduction. This study was designed to investigate whether 3-amino benzamide (3-AB), a poly (ADP-ribose) polymerase (PARP) inhibitor, has a protective effect on kidney injury induced by renal ischemia/reperfusion (I/R) by decreasing oxidative and nitrosative stress on renal dysfunction and injury. Materials and Methods. Thirty-two male Sprague-Dawley rats were divided into four groups: sham-operated, sham-operated + 3-AB, I/R, I/R + 3-AB. Rats were given 3-AB (100 mg/kg/day ip) 14 days prior to I/R. I/R and I/R + 3-AB groups underwent 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for evaluation. Superoxide dismutase, glutathione peroxidase, malondialdehide, protein carbonyl content, and nitrite/nitrate level (NOx) were determined in the renal tissue. Serum creatinine (SCr), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) were determined in the blood. Additionally, renal sections were used for histological grade of renal injury. Results. 3-AB significantly reduced the I/R-induced increases in SCr, BUN, and AST. In addition, 3-AB markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Moreover, 3-AB attenuated the tissue NOx levels, indicating reduced NO production. Conclusions. 3-AB has beneficial effect on renal glomerular and tubular dysfunction in rats' kidneys subjected to I/R injury. Moreover, 3-AB has ameliorating effect on both oxidative stress and nitrosative stress of the kidneys, which correlated with histopathological evaluation.  相似文献   
18.
In this study, the effects of the wound‐covering materials, Acticoat® and Cutinova Hydro®, on wound healing have been studied in rabbit models with open and tissue‐lost wounds with full‐thickness flank excisions. Rabbits were used as subjects with three groups of four rabbits each, and trial periods of 7, 14 and 21{\uns}days. Four circular wounds, of 1.5 cm diameter were made two on the right (one of them control) and two on the left (one of them control) of the dorsal sides of the abdomen. Acticoat® and Cutinova Hydro® were applied on the wounds with suture for a period of 21 days and one each placed on the right and left sides as control with gauze. Biopsy specimens were taken from the animals at the end of the research period to check the length of the epithelium, epithelial thickness, size of wounds, wound granulation tissue formation and histopathological evaluation for clarity. The Acticoat® group showed better healing and scar formation compared to the Cutinova Hydro® group by macroscopic examination. Epithelial wound length and clarity in terms of statistical difference occurred on day 21 (P <0.05); while the length of the wound epithelium decreased patency, epithelial thickness on days~7, 14 and 21, showed no statistical differences (P >0.05). As a result, the Acticoat® wound dressing was determined as a more reliable for the early wound healing. This study has shown the short‐term clinical benefits of hydroactive, polyurethane dressings in the management of acute wounds. However, longer periods of wound healing procedure should be planned for reliable and safe results of wound dressing. It has also been concluded that microbiological analyses should be included for more robust and reliable comparisons.  相似文献   
19.
BACKGROUND: Posterior spinal procedures through tubular exposures have been described. However, tubes restrain visibility and require co-axial instrument manipulation, increasing difficulty and potentially compromising surgical results. An independent-blade retractor system overcomes the obstacles of working through a tube and has been used to perform minimally-disruptive decompression and instrumented tranforaminal lumbar interbody fusion (TLIF). PURPOSE: To evaluate the advantages to patient recovery and surgical efficacy of this technique. METHODS/RESULTS: Retrospective review of technique employing a minimally-disruptive approach to decompression and transforaminal lumber interbody fusion (TLIF). CONCLUSIONS: Minimally-disruptive decompression and instrumented TLIF can be performed in a safe and effective manner using an independent-blade retractor system. Relative to traditional-open techniques, surgical goals can be accomplished, but with the benefits of minimally-disruptive surgery.  相似文献   
20.
Background  Type III supracondylar humeral fracture is a common cause of emergency hospitalization among children requiring surgical treatment. The configuration of the internal fixation material, surgical technique, and optimal timing of surgery (TS) have always been popular topics of debate. The TS in uncomplicated cases is usually determined by surgeons. Methods  In this study, we prospectively followed children with type III supracondylar fractures. We aimed to clarify the effects of injury side, gender, and post-injury delay on switching to open surgery and the ease of the reduction. Results  Based on our results, the probability of switching to open surgery increased by a factor of 4 every 5 h beginning 15 h after injury. Open surgery was necessary after 32 h. Conclusion  Reduction became technically more difficult as TS increased.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号